Combined spectral and UHR PCCT improved coronary stent assessment by balancing maximum spatial detail with more stable spectral reconstructions.
UHR images provided the best lumen visibility and lowest strut overestimation at 60 bpm, but image quality declined at higher heart rates because of motion sensitivity.
Spectral reconstructions, especially VMI 55 keV and iodine maps, offered more stable image quality across heart rates and may add value when UHR becomes motion-limited.
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Figure 2. Curved multiplanar reconstructions (MPR) at ultrahigh-spatial resolution of all analyzed stents with diameters and lengths. The appearance of contrast medium surrounding Stents 02 and 03 results from the fixed vessel geometry of the phantom and curved MPR projection, not from true luminal pathology. Notably, even in small-sized stents, clear lumen visualization was achievable.
Source: Hagar et al., European Radiology Experimental, 2025, Open Access
Protocol
Detail | Value |
|---|
Scanner | NAEOTOM Alpha |
Software | VB10 |
Scan mode | Quantum HD Retrospective ECG-gated spiral coronary CTA |
Tube voltage [kVp] | 120 |
Rotation time [s] | 0.25 |
Collimation | 96 × 0.2 mm |
Dose modulation | IQ level 64 |
Contrast agent | Ultravist 370 |
Contrast volume | 80 mL |
Saline flush | 50 mL |
Flow rate | 4 mL/s |
Bolus trigger | ROI in model aortic root |
Trigger threshold | 110 HU |
Post-trigger delay | 7 s |
Heart rates tested | 60, 80, 100 bpm |
Polychromatic UHR reconstruction | 0.2 mm slice thickness, 0.1 mm increment |
Spectral reconstruction thickness | 0.4 mm slice thickness, 0.2 mm increment |
Downsampled reconstruction | 0.6 mm slice thickness, 0.3 mm increment |
Kernel | Bv72 for UHR and spectral; Bv44 for downsampled |
Iterative reconstruction | QIR 3 |
Field of view | 205 × 205 mm |
Matrix size | 1024 × 1024 for UHR, 512 × 512 for spectral |
Spectral reconstructions | VMI 45, 55, 70, 85, 100 keV; PURE Lumen; iodine maps |
Hagar MT, Emrich T, Vecsey-Nagy M, et al. Spectral ultrahigh-resolution photon-counting CT for coronary stent imaging: evaluation in a dynamic phantom. Eur Radiol Exp. 2025;9:115. https://doi.org/10.1186/s41747-025-00654-2
